Insulated oil well cable



March 22, 1960 R. H. CARLSON 2,929,863

INSULATED OIL WELL CABLE Filed Oct. 17, 1956 fidj/ Z INVENTOR j/ k his Altar-nay cable be decreased as much as possible.

' numeral 2 indicates United States Patent 2,929,863 INSULATED OIL WELL CABLE Richard H. Carlson, Boylston, Mass., assignor to United States Steel Corporation, a corporation of New Jersey Application October 17, 1956, Serial No. 616,480 1 Claim. (Cl. 174-108) This invention relates to an electric cable and an insulating composition used therein. The invention while applicable to various types to a cable to be used in determining the characteristics of the strata at various levels in a deep oil well. Because of the conditions in deep oil wells, the insulating composition used must have certain characteristics which are present in prior used compositions which utilize natural rubber. However, in addition to these characteristics it is desirable that the weight and diameter of the The specific inductive capacity of insulating compositions used prior to my invention was relatively high, thus requiring a greater amount of insulation.

It is therefore an object of my invention to provide :an oil Well cable utilizing an insulating composition having a relatively low specific inductive capacity while re- :taming substantially the physical characteristics of the prior insulating compositions.

This and other objects would be more apparent after referring to the following specification and attached drawing, in which the single figure is a view of a well logging cable with parts broken away.

Referring more particularly to the drawings, reference electrical conductors or strands each of which is made up of seven coated copper wires laid with a left hand lay. Insulating material 4 surrounds each of the conductors 2. It is this insulating material to which the present invention relates. The insulating material 1s extruded about each of the conductors in the usual manner. An electrical shielding compound 6 surrounds the insulating material 4 on each conductor 2.

conductors 2. A binder 10 of cotton or similar material 1s hehcally wound about sition as the layer 6. A first layer of eighteen armor wires 18 surrounds the shielding compound and a second layer of eighteen armor wires 20 surrounds the first layer 18. The wires in the two layers are laid with opposite lay and it is preferred that the wires in the first layer be right lay and those in the second layer left lay. It will be understood that the number of conductors in the cable may vary, as many as seven conductors commonly being used.

The insulating composition of my invention includes 40 to 50 percent by weight of butadiene-styrene polymer in which there is approximately three times as much butadiene as styrene. The polymer may include slight amount;

of other materials such as a fraction of one percent of divinylbenzene. More than one type of polymer may be used as long as the ratio of butadiene-styrene does not vary more than a few percent. The composition also in eludes 12 to 16% by weight of a butadiene-styrene copolymer having approximately 15% (14% to 16%) butadiene and approximately (84% to 86%) styrene, 0.6 to 1.0% by weight of a peptizer, 4 to 6% by weight of zinc oxide, 12 to 17% by weight of talc, 13 to 17% by weight of calcined clay, .50 to 1.5% by weight of an antioxidant, 1.0 to 2.0% by Weight of parafiin wax, 0.30 to 0.70% by weight of fatty acid, 0.75 to 1.00% by weight of sulphur, 0.50 to 0.80% by weight of an accelerator, and 0.30 to 0.50% by weight of activator. A particular composition found to be suitable includes 29% of the composition GR-S-l019 and 16% of the composition GR-S-1018, these making up the butadiene-styrene polymer having approximately three times as much butadiene as styrene, 14% butadiene-styrene copolymer having 15% butadiene and 85 styrene, .88% naphthyl-beta mercaptan, this being the peptizer, 5% zinc oxide, 15.22% talc ground to 300 mesh or finer, 15 calcined clay, 1.00% 4 metl1yl-6-tertiary butyl phenol, this being the anti-oxidant, 1.50% parafiin wax, .50% stearic acid, 1.00% sulfur, .50% zinc dimethyl dithiocarbamate, this being the accelerator, and .40% mercaptobenzothiazole, this being the activator.

The butadiene-styrene polymers are the electrical grades of the polymers of butadiene and styrene which provide low water absorption because they have been treated to keep the water soluble ash and electrolyte at a minimum. The terms used above are well known in the art and are defined in the Glossary of Terms Relating to Rubber and Rubber-Like Materials published by the American Society for Testing Materials.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claim.

I claim:

An oil well cable comprising a plurality of conductors twisted together, an insulating material surrounding each of said conductors, a filler in the valleys between the conductors, a binder surrounding said filler and conductors, and a layer of armor wires surrounding said binder, said insulating material consisting essentially of 40 to 50% by weight of butadiene-styrene copolymer in which there is approximately three times as much butadiene as styrene, 12 to 16% by weight of butadiene-styrene copolymer in which there is approximately 15 butadiene and 85% styrene, 0.6 to 1.00% by weight of peptizer, 4 to 6% by weight of zinc oxide, 12 to 17% by weight of talc, 13 to 17% by weight of calcined clay, 0.5 to 1.5% by Weight of an anti-oxidant, 1.0 to 2.0% by weight of paraflin wax, 0.30 to 0.70% by weight of fatty acid, 0.75 to 1.00% by weight of sulphur, 0.50 to 0.80% by weight of accelerator, and 0.30 to 0.50% by weight of activator.

References Cited in the file of this patent The India-Rubber Journal, November 12, 1927, pages 897, 898. 

